Base-Promoted Synthesis of S -Arylisothiazolones via Intramolecular Dehydrative Cyclization of α-Keto- N -acylsulfoximines.

A base (Et 3 N)-promoted synthesis of 1,4-diarylisothiazolones from α-keto- N -acylsulfoximines has been achieved. The reaction proceeds via α-hydrogen abstraction from sulfoximine, followed by an intramolecular nucleophilic attack at the keto carbonyl to form a tert -hydroxy isothiazolone intermediate. The 1,4-substituted isothiazolone is obtained after dehydration via an E1cB path. This one-pot synthesis of isothiazolinones has a broad substrate scope, has a high atom economy, and provides products with good yields. The Δ E LUMO-HOMO is calculated using Gaussian 16 at the B3LYP/6-31G(d,p) level of theory.